Various other separators have been considered by Hurtado et. al, such as wedges, strips [1]}, and double wedges [2]} in 2D.
All these separation problems can be decided in \(O(n \log n)\)  time [2]}, [1]}.
They also extend the single and double wedge separability to 3D and consider separability by other 3D geometric loci, such as prisms and pyramids [5]}, for which they describe polynomial-time algorithms.
Demaine et. al studied the separability by line segments, chords, and multi-chords [6]}, for which they give polynomial time algorithms and also prove lower bounds.
